In recent years, the importance of an optically active compound has increased even more, and a process for selectively and efficiently producing a pure optically active chiral molecule from the viewpoint of research and development not only of pharmaceuticals but also of functional materials is indispensable.
The optical resolution by HPLC is developed as a process which can be used for both fractionation and microanalysis, and there has been progress in the development of various chiral fillers. Of those, a substance obtained by converting a polysaccharide which abundantly exists in nature, such as cellulose and amylose, to a phenylcarbamate derivative is widely used because such a substance has an excellent optical resolution ability to various kinds of racemates including pharmaceuticals, as a chiral stationary phase for HPLC.
In the chiral stationary phase using those polysaccharide derivatives, used as a filler is a derivative which is physically adsorbed on or chemically bonded to silica gel serving as a carrier. However, such a filler that is supported on silica gel in the above-mentioned manner cannot use, as an eluent, a solvent in which a polysaccharide derivative is swollen and/or dissolved. Further, the proportion of the polysaccharide derivative contained in the filler is small, and substantially, only the polysaccharide derivative on the surface of silica gel is used for optical resolution. Thus, in such a filler, there is room for improvement as a filler for fractionation.
JP-B-7-63622 discloses a separating agent formed of particles of 7 to 13 μm obtained by crushing and classifying polysaccharide derivatives in which 10% or more of hydroxyl groups were substituted with a carbamoyl group. Further, JP-B-7-63622 discloses, on page 2, column 4 that crosslinking may be performed as required, but there is no specific description.